Systems and Methods for Real-Time Sweat Sampling and Analysis

ABSTRACT

Systems and methods for continuous real-time sweat sampling and analysis are disclosed. In one case, a sweat collection device and method of using the same are provided. The sweat collecting device has a main body with a sweat-collecting surface that is placed adjacent the person&#39;s skin. A sweat collecting tube is provided. The first end of the sweat collecting tube is joined to a bore in the main body of the device and the second end extends outward therefrom. In another case, a sweat collection article and method of collecting sweat from a person&#39;s skin using the sweat collection article are provided. The sweat collection article includes: a sweat collecting tube placed adjacent to the person&#39;s skin, and at least one piece of flexible material that has an adhesive that adheres the article to the person&#39;s skin and is positioned to overlie one end of the tube. In both cases, the second end of the sweat collecting tube is in fluid communication with an instrument such as a mass spectrometer that analyzes the sweat on a real-time basis. The systems and methods may further include a device for removing salt from the sweat that is arranged so that the sweat is transported to the device prior to being transported to the instrument for analyzing the sweat.

Pursuant to 37 C.F.R. § 1.78(a)(4), this application claims the benefitof and priority to prior filed co-pending Provisional Application Ser.No. 63/083,403, filed Sep. 25, 2020, which is expressly incorporatedherein by reference.

RIGHTS OF THE GOVERNMENT

The invention described herein may be manufactured and used by or forthe Government of the United States for all governmental purposeswithout the payment of any royalty.

FIELD OF THE INVENTION

The present invention relates generally to the collection of human sweatfor analytical evaluation and, more particularly, to systems and methodsfor real-time sweat sampling and analysis.

BACKGROUND OF THE INVENTION

Sweat has become an emerging biosource for biomarker discovery tosustain or enhance human performance. Typically, single large bulk sweatsamples are collected for later off-line analysis. While useful, thissampling strategy limits the time-resolution of often-lengthy collectionevents and the utility of identified markers.

Historically, the most widely used method for sweat collections involvesa single sample, obtained via a “patch” or other device, collected overthe course of an entire experiment, such as an exercise or sweatstimulation regime. Therefore, the sample collected is onlyrepresentative of the mean analyte concentration over the experimentaltime. As a result, changes of analytes, e.g. ions and metabolites, overthe time course of the experiment are lost.

Therefore, a need exists for a system and method for real-time sweatsampling and analysis to better elucidate any changes in properties ofthe sweat and/or analyte concentration that may occur during the courseof an experiment.

SUMMARY OF THE INVENTION

While the invention will be described in connection with certainembodiments, it will be understood that the invention is not limited tothese embodiments. To the contrary, this invention includes allalternatives, modifications, and equivalents as may be included withinthe spirit and scope of the present invention.

The present invention relates generally to the collection of human sweatfor analytical evaluation and, more particularly, to systems and methodsfor continuous real-time sweat sampling and analysis. Severalembodiments of the sweat collection and analysis system are describedherein.

The first embodiment provides a continuous real-time sweat collectionsystem comprising a sweat collecting device comprising a main bodyhaving two surfaces comprising a sweat-collecting surface and anopposing outwardly-oriented surface. The sweat-collecting surface has aconcave configuration which defines a rim lying wholly within a commonplane. The main body has an axial bore extending between thesweat-collecting surface and the outwardly-oriented surface. A length ofsweat collector tubing has one end joined to the main body at the axialbore and a free end that extends outwardly from the outwardly-orientedsurface of the main body. The free end of the sweat collector tubing isin fluid communication with the input or source of a detector orinstrument such as a mass spectrometer.

The method of using the first embodiment of the sweat collection systemcomprises:

-   -   a) placing a sweat collection device over an area of the        person's skin, wherein the sweat collection device comprises:    -   a main body having two surfaces comprising a sweat-collecting        surface and an opposing outwardly-oriented surface, wherein the        sweat-collecting surface has a concave configuration which        defines a rim lying wholly within a common plane, wherein the        main body has an axial bore extending between the        sweat-collecting surface and the outwardly-oriented surface; and    -   a length of sweat collector tubing having one end joined to the        main body at the axial bore and a free end extending outwardly        from the outwardly-oriented surface of the main body;    -   b) placing the free end of the sweat collector tubing in fluid        communication with the input port of an instrument for analyzing        sweat;

c) collecting sweat from the person's skin using the sweat collectiondevice wherein sweat travels into the sweat collector tubing and theninto the instrument; and

d) analyzing the sweat collected using the instrument.

The second embodiment provides a continuous real-time sweat collectionsystem which comprises a sweat collecting article and a sweat collectortube. The sweat collecting article comprises a thin, flexible,conformable, and impervious covering. The covering has two surfacescomprising a body-facing surface and an opposing outwardly-orientedsurface. The covering comprises a central portion, edges that define aperimeter, and a perimeter portion surrounding the central portion. Thecentral portion of the body-facing surface is free of adhesive. Theperimeter portion has adhesive on the body-facing surface for adheringthe covering to a person's skin and for forming a seal around thecentral portion.

In the second embodiment, the sweat collector tube has a first end, asecond end, and a length that extends between the first and second ends.The first end of the sweat collector tube is positioned adjacent to thecovering so that the central portion of the covering overlaps a firstportion of the tube. A second portion of the tube extends outward beyondone edge of the central portion of the covering and is adjacent to andis joined to the adhesive on the perimeter portion of the covering. Athird portion of the tube extends beyond an edge of the covering to thesecond end of the tube. The second end of the tube is free to be placedin fluid communication with an instrument for analyzing the sweat.

The method of using the second embodiment of the sweat collection systemcomprises:

a) attaching a sweat collection article over an area of the person'sskin, wherein the sweat collection article comprises:

-   -   a sweat collector tube having a first end and a second end,        wherein the first end of the tube is placed adjacent the area of        the person's skin, and the second end of sweat collector tube is        free to be placed in fluid communication with an instrument for        analyzing sweat; and    -   a thin, flexible, conformable, and impervious covering that is        positioned over and adhered to the sweat collector tube, the        covering having two surfaces comprising a body-facing surface        and an opposing outwardly-oriented surface, a central portion,        edges that define a perimeter of said central portion, and a        perimeter portion surrounding the central portion, wherein the        central portion of the body-facing surface is free of adhesive,        and the central portion of the covering is placed over the first        end of the sweat collector tube, and the perimeter portion has        adhesive on the body-facing surface for adhering the covering to        a person's skin and for forming a seal around the central        portion;    -   b) placing the free second end of the sweat collector tube in        fluid communication with the input port of an instrument for        analyzing sweat;    -   c) collecting sweat from the person's skin using the sweat        collection device wherein sweat travels into the sweat collector        tubing and then into the instrument; and    -   d) analyzing the sweat collected using the instrument.

In addition, in any of the embodiments described above, or in otherembodiments, salt may be removed from the sweat before it is transportedto an instrument for analyzing sweat. An example of such an embodimentis a continuous real-time sweat collection and analysis systemcomprising:

a sweat collecting device comprising:

-   -   an article that is to be placed in contact with an area of a        person's skin, the article having a skin-facing surface, wherein        the article is configured to collect sweat between the area of        skin and the skin-facing surface; and    -   a sweat collector tube having one end that is positioned        adjacent to the article and in position to withdraw and        transport sweat collected between the area of skin and the        skin-facing surface of the article, the tube extending outwardly        from the article to a free end;

a device for removing salt from the sweat, the device having an inputport and an output port, wherein the free end of the sweat collectortubing is in fluid communication with the input port of the device forremoving salt from the sweat; and

an instrument for analyzing sweat having an input port, wherein theinput port of the instrument is in fluid communication with the outputport of the device for removing salt from the sweat.

Additional objects, advantages, and novel features of the invention willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and attained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentinvention and, together with a general description of the inventiongiven above, and the detailed description of the embodiments givenbelow, serve to explain the principles of the present invention.

FIG. 1 is a perspective view of a prior art sweat collection deviceattached to a portion of a wearer's forearm.

FIG. 2 is a perspective view of a first embodiment of sweat collectiondevice shown on a person's arm oriented downward as it might be if theperson is on a treadmill.

FIG. 3 is a perspective view of a second embodiment of the sweatcollection device described herein attached to a portion of a wearer'sforearm.

FIG. 4 is a bottom plan view of one version of the second embodiment ofthe sweat collection device.

FIG. 5 is an exploded perspective view of another version the sweatcollection device shown in FIG. 3.

FIG. 6 is a schematic side view of a sweat collection and analysissystem comprising a device for removing salt from the sweat before it istransported to an instrument for analysis.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the sequence of operations as disclosedherein, including, for example, specific dimensions, orientations,locations, and shapes of various illustrated components, will bedetermined in part by the particular intended application and useenvironment. Certain features of the illustrated embodiments have beenenlarged or distorted relative to others to facilitate visualization andclear understanding. In particular, thin features may be thickened, forexample, for clarity or illustration.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to the collection of human sweatfor analytical evaluation and, more particularly, to systems and methodsfor continuous real-time sweat sampling and analysis.

FIG. 1 shows a prior art sweat collection device 10 attached to aportion of a person's forearm. The prior art sweat collection device 10shown is a MEGADUCT® sweat testing device sold by ELITechGroup of Logan,Utah, U.S.A. ELITechGroup also sells a similar, but smaller MACRODUCT®sweat collection device. These products and the procedure for using thesame are described in greater detail in U.S. Pat. No. 4,383,529, Websterand U.S. Pat. No. 4,542,751, Webster, et al. The sweat collection device10 is typically used in a process to determine the concentration ofsodium and chloride in the sweat of children suffering from cysticfibrosis. U.S. Pat. No. 4,383,529, Webster discloses an iontophoreticelectrode device that is used with an iontophoretic drug such aspilocarpine to induce sweating at a selected area of a person's skinprior to placing the sweat collection device against the person's skin.Certain improvements to these products are described in U.S. Pat. No.6,198,953 B1, Webster, et al. and U.S. Pat. No. 9,226,730 B2, Briscoe,et al.

The MEGADUCT® sweat collection device 10, as described in theaforementioned patents, comprises a solid body 12 having a concave meansdefined at a face thereof by a sweat-collecting surface 14 whichgradually recedes from a rim lying wholly within a common plane. In FIG.1, the sweat-collecting surface 14 is facing the wearer's skin. An axialbore 16 extends from the sweat-collecting surface to the opposite face18 of the solid body. The maximum depth of the concave means is suchthat the skin and flesh of the flat area of a human body to which thedevice is applied will bulge into contact with the sweat-collectingsurface 14 over substantially the entire area thereof when the rim isplaced firmly against the skin of the flat area of the human body,leaving substantially no dead space in the interface between the bulgedskin and the sweat-collecting surface 14. The body secretion pressure ofsweat will force sweat through the interface to the axial bore 16. Theaxial bore 16 is adapted to connect with a length of flexible, sweatcollector tubing 20 at the opposite face 18 of the solid body 12. Thesweat collector tubing 20 is coiled in a flat, spiral formation and ispositioned within a recessed receiving chamber 22 on the face 18 of thebody 12 opposite the sweat-collecting surface 14. The solid body 12 isfastened against the flat area of a portion 26 of a human body such asby straps 24 so as to maintain firm placement of the rim andsweat-collecting surface 14 against the skin.

U.S. Pat. No. 4,542,751, Webster, et al. describes how the sample ofsweat is obtained when using the MEGADUCT® sweat collection device afterit is collected in the spiral tubing. The tubing 20 has to bedisconnected from the axial bore 16. The sweat then has to be expelledfrom the tubing 20 into a testing vessel by inserting an elastomer bulbinto one end of the tubing 20 and squeezing the bulb. As a result, allof the sweat collected in the tubing is mixed together in the testingvessel. Because of this, it is not possible to analyze samples of sweatobtained at different times during the collection period.

FIG. 2 shows a first embodiment of the sweat collecting device used inthe sweat collection and analysis system and method of the presentinvention. This sweat collecting device and sweat collection andanalysis system and method constitutes an improvement over theMACRODUCT® and MEGADUCT® sweat collection devices and current proceduresfor using the same in order to provide continuous real-time sweatsampling and analysis.

The term “continuous”, as used herein, refers to sampling and analysisthat takes place on an uninterrupted basis from the time the analyticalinstrument is started and sweat is received by the instrument. It isalso within the scope of the present invention, however, for the sweatcollection and analysis systems and methods to be operated in anon-continuous manner by interrupting the sampling and analysis, ifdesired.

The term “real-time”, as used herein, refers to a process in which theanalysis is taking place as the sweat is being collected, rather than aprocess that involves collecting and storing the sweat for lateranalysis. The analysis will occur without placing the sweat in aseparate container prior to conducting the analysis. Instead, the sweatmay be transported by a conduit or tube directly to an analyticalinstrument (or after it has been processed by removing salt from thesame as described herein). The time period in which the analysis mayoccur may be less than or equal to any of the following time periodsafter the generation of the sweat being analyzed: 15, 10, 5, 3, 2, or 1minutes.

The terms “tube” and “tubing” may be used interchangeably herein. Thetubing referred to herein is typically flexible along its entire length,although it is possible for portions of the tubing that do not move orconform to the body of the test subject during use to be relativelyrigid.

The first embodiment of the sweat collection system 30 comprises a sweatcollecting device 32 comprising a main body 34 and a length of sweatcollector tubing 36. The main body 34 has two surfaces comprising asweat-collecting surface 38 and an opposing outwardly-oriented surface40. The sweat-collecting surface 38 has a concave configuration whichdefines a rim lying wholly within a common plane. The main body 34 hasan axial bore 42 extending between the sweat-collecting surface 38 andthe outwardly-oriented surface 40. The axial bore 42 is covered by othercomponents in FIG. 2, but it is in the location of the end of the leadline pointing to the same. The sweat collecting tubing 36 has a firstend 36A joined to the main body 34 at the axial bore 42, and extendsoutwardly from the outwardly-oriented surface 40 of the main body 34 ofthe sweat collecting device 32 to a free second end 36B that is in fluidcommunication with an instrument for analyzing sweat (such an instrumentis shown in FIG. 6).

The sweat collector tubing (or “tube”) 36 should have a length and aninside diameter that permits the transport of sweat therethrough at arate which is sufficient to provide the sweat to an instrument foranalyzing the sweat on a continuous real-time basis, or approximatelyreal-time basis. It may be desirable for the person from whom sweat isbeing collected to be positioned close to the instrument to ensure thatthere is minimal delay between the sweat collection and the analysis. Insome cases, it may, for example, be desirable for the participant to bewithin about 0.5 meter of the instrument. The length of the tubing 36may, therefore, be less than or equal to about 0.5, 0.6, or 0.7 meter,or more. The inside diameter of the tubing 36 can be any size that is asmall enough to transport sweat under the body secretion pressure yetlarge enough to transport a sufficient amount of the sweat to theinstrument for analysis on a real-time basis. The inside diameter of thetubing should also be sufficiently small that there is substantially nomixing of the sweat obtained at various times during the sweatcollection process. The inside diameter of the tubing 36 may be lessthan 0.85 mm, or less than (or less than or equal to about) 0.8 mm or0.75 mm. In one embodiment, the tubing 36 has an inside diameter ofabout 0.01 inch (about 0.25 mm). Thus, the inside diameter of the tubing36 may range from about 0.01 inch (about 0.25 mm) or less (e.g., about0.2 mm) up to 0.85 mm. The sweat collector tube 36 can comprise anysuitable material including, but not limited to polyetheretherketone(PEEK) tubing.

The main body 34 of the device can have a support 44 joined thereto suchas to the outwardly-oriented surface 40 of the same for supporting thesweat collector tubing 36 during the sweat collection activity. Thesupport 44 can comprise any suitable member or structure. The support 44shown in FIG. 2 comprises a plastic dowel that is placed adjacent to thetubing so that it runs along the length of a section of the tubing thatextends from the outwardly-oriented surface 40 of the main body 34 ofthe device, and the dowel and section of tubing are held together with aheat shrink wrap.

The first embodiment of the sweat collection device 32 can be made bymodifying a MEGADUCT® sweat collecting device by removing the sweatcollector tubing that is provided. The main body 34 of the sweatcollection device 32 may, thus, have any of the properties of the solidbody of the MEGADUCT® device described above. The sweat collector tubing20 that is supplied with the MEGADUCT® device has an inside diameter ofabout 0.86 mm (about 0.34 inches) according to the patents referencedabove. While this is suitable for collecting and storing sweat, it isnot suitable for transporting sweat therethrough at a rate which issufficient to provide the sweat to an instrument for analyzing the sweaton a real-time basis. It is estimated that the MEGADUCT® tubing mayrequire as much as one hour to transport a sufficient quantity of sweatfor analysis. The sweat collector tubing can be replaced with the PEEKtubing described above.

The free second end 36B of the sweat collector tubing 36 is placed influid communication (directly, or indirectly) with the input (or source)46A of a detector or instrument for analyzing sweat 46 as shown in FIG.6. The instrument for analyzing sweat 46 may be any suitable type ofinstrument that provides information about the composition of the sweat,particularly on a continuous, real time basis. Suitable instrumentsinclude, but are not limited to mass spectrometers, UVspectrophotometers, ion chromatography devices, proton-transfer-reactionmass spectrometers (PTR-MS). Any suitable type of mass spectrometer thatallows the sweat to be analyzed on a continuous, real time basis can beused. Suitable types include electrospray ionization (ESI) massspectrometers. One suitable ESI mass spectrometer is a FUSION LUMOS™available from Thermo Fisher Scientific of Waltham, Mass., U.S.A.

FIG. 3 shows a second embodiment of a sweat collection device comprisinga sweat collecting article 52 that is used in the sweat collection andanalysis system and method of the present invention. The secondembodiment of a sweat collection device is shown attached to a portion26 of a wearer's forearm. The sweat collecting article 52 comprises acovering 54 and a sweat collector tube 56. Two versions of the secondembodiment of the sweat collecting article 52 are shown in the drawings.

FIG. 4 shows a first version of the sweat collecting article 52 of thesecond embodiment. The first version is a simplified version of thesweat collection article 52 shown on the person's arm in FIG. 3. Asshown in FIG. 4, the sweat collecting article 52 comprises a thin,flexible, conformable, and impervious covering 54. The term “thin”, asused herein, means that the covering 54 has a thickness of less than orequal to about 1 mm. The term “flexible”, as used herein, means that thecovering 54 will bend under the forces associated with applying thecovering 54 to a part of a wearer's body, similar to those forcesassociated used in applying a bandage or wound dressing to a wound. Theterm “conformable”, as used herein, means that the covering 54 willconform to the configuration of the part of the wearer's body to whichit is applied. It may also be desirable for the covering 54 to be atleast semi-transparent so that a person conducting the test will be ableto see through the covering 54 sufficiently to see when sweat is beingcollected.

The covering 54 has two surfaces comprising a body-facing surface 58 andan opposing outwardly-oriented surface 60. The covering 54 comprises acentral portion 62, edges that define a perimeter 64 of the centralportion 62, and a perimeter portion 66 surrounding the central portion62. The central portion 62 of the body-facing surface 58 is free ofadhesive. The perimeter portion 66 has adhesive 68 on the body-facingsurface 58 for adhering the covering 56 to a person's skin and forforming a seal around the central portion 62. The adhesive 68substantially or completely surrounds the central portion 62 to keep thecentral portion 62 in sufficiently close contact with the wearer's skinso that it does not form a gap or bubble adjacent the wearer's skin andforms a seal to prevent sweat from leaving the area of the wearer's skincovered by the central portion 62, other than through the sweatcollector tube 56.

As shown in FIG. 4, the sweat collector tube 56 (which is shown aspartially fragmented) has a first end 56A, a second end 56B, and alength that extends between the first and second ends. The first end 56Aof the sweat collector tube 56 is positioned adjacent to the covering 54so that the central portion 62 of the covering overlaps a first portion70 of the tube. A second portion 72 of the tube 56 extends outwardbeyond one edge of the central portion 62 of the covering 54 and isadjacent to and is joined to the adhesive 68 on the perimeter portion 66of the covering. A third portion 74 of the tube 56 extends beyond anedge of the covering 54 to the second end of the tube 56B. The secondend 56B of the tube 56 is free to join to an instrument for analyzingthe sweat.

FIG. 5 shows the assembly of the components of another version of thesweat collecting article 52 of the second embodiment. This is similar tothe sweat collecting article 52 shown in FIG. 3. In the sweat collectingarticle 52 shown in FIG. 5, the covering 54 comprises two piecescomprising a first piece of flexible film material 80 and a second pieceof flexible film material 82 with adhesive thereon. The sweat collectingarticle 52 shown in FIG. 5 is otherwise similar to the sweat collectionarticle 52 shown in FIG. 4. Similar components, such as the tube will,therefore, be given the same numbers. This version of the sweatcollecting article may be thought of as a pouch (in the nature of akangaroo pouch where one part of the pouch is formed by the body of theperson wearing the sweat collecting article). It may also be thought ofas a laminate.

The first piece of flexible film material 80 has two surfaces comprisinga body-facing surface 84 and an opposing outwardly-oriented surface 86,an area, and edges 88 that define a perimeter 90. The first piece offlexible film material 80 fits against the person's skin and entrapssweat between the person's skin and the body-facing surface 84 of thematerial. The first piece of flexible film 80 should be liquid and vaporimpervious, non-porous, non-absorbent, and conformable. The first pieceof flexible film 80 may be inextensible. The first piece of flexiblefilm material 80 can comprise any suitable flexible film includingpolymeric films, such as polyethylene or polypropylene. It may bedesirable for the film to comprise virgin, rather than recycledpolymeric material, to minimize the presence of contaminants. The firstpiece of flexible film 80 can be of any size suitable for covering aportion of a person's skin from which sweat will be collected. The sizecan vary depending on the experiment. In one case, the first piece offlexible film 80 comprises a small piece of plastic film (e.g., betweenabout 2.5-3 inches in length by about 1¼ inch in width).

The second piece of flexible film material 82 has two surfacescomprising a body-facing surface 94 with adhesive thereon and anopposing outwardly-oriented surface 96. The second piece of filmmaterial 82 with adhesive thereon is sized and configured to extendbeyond all of the edges 88 of the first piece of film material 80. Thesecond piece of flexible film 82 may be liquid impervious,non-absorbent, and conformable, and it may also be moisture vaporpermeable and extensible under the forces associated with attaching thesecond piece of film 82 to a person's skin. The second piece of flexiblefilm material 82 can comprise any suitable flexible film includingpolymeric films, such as virgin polyethylene or polypropylene. Thebody-facing surface 94 of the second piece of flexible film material 82has an adhesive 102 thereon for adhering to the outwardly-orientedsurface 86 of the first piece of film material 80 and a person's skin.The adhesive 102 should be suitable for removably attaching the secondpiece of film 82 to a person's skin. The second piece of film 82 withadhesive thereon can comprise a commercially available bandage materialsuch as OP SITE® transparent waterproof film manufactured by Smith &Nephew, Inc. Advanced Wound Management of Ft. Worth, Tex., U.S.A, orTEGADERM™ transparent medical dressing manufactured by 3M™ of St. Paul,Minn., U.S.A.

The sweat collector tube 56 in the second embodiment has a first end56A, a second end 56B, and a body having a length that extends betweenthe first and second ends. The tubing 56 can be the same type and havethe same properties as the tubing 36 used above with the firstembodiment of the sweat collecting device 32. In the second embodiment,the first end 56A of the sweat collector tube 56 is positioned adjacentto the first piece of film material 80 so that the first piece of filmmaterial 80 overlaps a first portion of the tube 70. A second portion 72of the tube 56 extends outward beyond one edge of the first piece offilm 80 and is adjacent to, and is joined to a portion of the adhesive102 on the second piece of film material 82. The portions of adhesiveadjacent to the second portion 72 of the tube 56 may hold the secondportion 72 of the tube 56 adjacent to the wearer's skin. A third portion74 of the tube 56 extends beyond the second piece of film material 82 tothe second end 56B of the tube. The second end 56B of the tube is freeto join to (and/or to be in fluid communication with) an instrument foranalyzing the sweat.

The method of using the second embodiment of the sweat collection systemcomprises attaching the sweat collection article over an area of theperson's skin. The sweat collection article can be attached to anysuitable portion of the person's body from which a sweat sample can beobtained. For example, the sweat collection article can be attached tothe inside of a person's forearm.

The sweat collection article 52 can be pre-assembled and placed on theperson's skin; or it can be assembled as it is placed on the person'sskin. In either case, the relationship of the components will be thesame. The following will describe assembly of the sweat collectionarticle on the person's skin. The first end 56A of the tubing 56 isplaced adjacent the area of the person's skin. Next, a small first pieceof plastic film 80 is placed over the first end of the tube 56A so thatthe first piece of film 80 overlies the first end 56A of the sweatcollector tubing 56. There may be a small space between the wearer'sskin and the first piece of film 80 to prevent the skin from adhering tofirst piece of material 80. A second piece of film material 82 withadhesive thereon that is larger than the first piece of film 80 is thenobtained. If the second piece of film 82 is in the form of an adhesivebandage, any protective covering on the adhesive is first removed. Thesecond piece of film 82 is applied over the first piece of film 80 sothat its edges extend outward from the edges of the small first piece ofplastic film 80. The second piece of film material 82 comprises a firstportion of adhesive that adheres to the outwardly-oriented surface 86 ofthe first piece of film material 80 and a second portion of adhesivethat adheres to a person's skin. The first and second portions ofadhesive on the body-facing surface 94 of the second piece of film 82may be separated or contiguous. The sweat collector tubing 56 extendsoutward from under the first and second pieces of film material 80 and82 to its second end 56B, while the second portion of adhesive adherespart of the tubing 56 to the wearer's skin. The second end 56B of thesweat collector tubing 56 is placed in fluid communication with aninstrument for analyzing sweat, and sweat is collected from the person'sskin using the sweat collection article wherein sweat travels into thesweat collector tubing 56 and then into the instrument.

The size of the first and second pieces of film 80 and 82 can beadjusted based on the use/type of exercise. The location of the firstend 56A of the tubing 56 and the angle that the tubing 56 makes relativeto the vertical direction may also be set depending on the type ofexercise. For example, if the subject is walking or running on atreadmill, the tube 56 may be oriented downward, since their forearmswill be oriented downward. If the subject is on an exercise bike, thentheir arm will be oriented more horizontally or even with their handelevated above their elbow. In the latter case, the tubing 56 may beoriented generally horizontally. In either case, it is desirable toposition the first end 56A of the tubing 56 at a location under thefirst piece of film 80 where sweat will most likely flow by gravity.

The second embodiment is utilized by asking participants to perform asweat collection either through stimulation, heat acclimation, orexercise with the invention worn on a part of their body. It is notnecessary to induce sweating through the use of iontophoretictransporting of drug molecules through the skin. The sweat collectionarticle 52 can be placed on the wearer's skin first, and then the personcan be instructed to engage in the specified activity. Alternatively,but less desirably, the person may be instructed to initiate thespecified exercise, and before the person begins generating sweat, thesweat collection article 52 can be placed on the wearer's skin. As inthe case of the first embodiment, it may be desirable for theparticipant to be positioned close to the instrument to ensure thatthere is minimal delay between the sweat collection and the analysis. Itmay, for example, be desirable for the participant to be within about0.5 meter of the instrument.

The prior art MEGADUCT® device shown in FIG. 1 is generally used toobtain sweat samples which are used to measure for salt content. Otherdevices or sensors that may have been used for real time analysis ofsweat are typically limited to detecting a single predeterminedsubstance, or a limited number of predetermined substances (e.g., lessthan or equal to five substances) that are known to be present in sweat.The devices and methods of the present invention, on the other hand, areused to discover any substances that may be contained in sweat. Thedevices and methods of the present invention are also used to determinehow the presence or intensity (or abundance) of such substances in sweatmay change over the period of collection. The present invention may, forinstance, be used to measure for lipids, amino acids, metabolitescontinuously throughout the collection period. The methods of thepresent invention can measure for multiple analytes at the same time.For instance, the methods of the present invention can measure for sixor more different analytes up to a relatively unlimited number ofdifferent analytes (e.g., a thousand or more different analytes). Incertain cases, it may be desirable to detect between about 50 and about500 different analytes at a given time. A scan can be run every secondor less (even every millisecond, or every microsecond) on the collectedsweat that is transported to the instrument for analyzing sweat. Thesamples can be analyzed in real time for any substances including, butnot limited to the presence of biomarkers as described in U.S. patentapplication Ser. No. 16/431,326, filed on Jun. 4, 2019 and published asU.S. Patent application Publication US 2019/0365298 A1, Harshman, et al.The metabolites listed in Table 4 of the Harshman, et al. patentapplication are of particular interest.

In some embodiments, as shown in FIG. 6, it may be desirable tointerpose a step of desalting (or desalinating) the sweat sample priorto analysis by the instrument for analyzing sweat 46. Without wishing tobe bound by any particular theory, it is believed that the high saltcontent of sweat may interfere with the real-time detection of variousanalytes and biomarkers in sweat due to ion suppression caused by thehigh salt content. The step of desalting the sweat involves removingsalt ions such as Na⁺, Cl⁻, F⁻, NH₄ ⁺, K⁺, and Ca²⁺ from the sweat,without removing other analytes of interest like amino acids and aminoacid-like compounds (e.g., molecular weight approximately 50-170 Da).This step removes the salt ions in the sweat (that can be viewed ascontaminants) which may improve the instrument's ability to detect otheranalytes in lower quantities.

Suitable mechanisms for removing salt include, but are not limited toelectrodialysis, micro dialysis, and ion concentration polarization.Such microfluidic devices 48 having an input port 48A and an output port48B can be connected in-line between the sweat collecting device 32 or52 and the instrument for analyzing sweat 46. Passing the sweat throughsuch devices will not result in an appreciable time delay in thereal-time analysis of the collected sweat because the sweat can flowthrough such devices relatively quickly. For instance, electrodialysisis a membrane separation technology in which the ionized species areallowed to pass through an ion-exchange membrane by means of an externalapplied electric field. Microdialysis is a minimally-invasive samplingtechnique that is typically used for continuous measurement of free,unbound analyte concentrations in the extracellular fluid of virtuallyany tissue. As a result, the device 48 will provide a real-time rate ofthe migration of sweat from the individual to the instrument foranalyzing sweat 46 to facilitate quantitative determination of changesin analyte abundance over time.

Various alternative embodiments of the systems and methods forcollecting sweat over a period of time are possible. It is understoodthat several of the aforementioned steps can be performed in anysuitable order. For instance, the method may involve attaching the sweatcollection device over a person's skin before or after sweating isinduced. In addition, in the second embodiment, the sweat collectionarticle can be assembled first and attached to the wearer's skin; or itcan be assembled on the wearer's skin by placing the tube

against the wearer's skin and then placing the covering on top of thetube. The free end of the sweat collector tubing may be placed in fluidcommunication with the input port of an instrument for analyzing sweateither before or after the sweat collection device is placed on aperson's skin. In addition, although collection and analysis of sweatfrom humans is primarily of interest, the system and method of thepresent invention could be used with any other biological subject thatis capable of producing and excreting sweat.

The systems and methods for real-time sweat sampling and analysisdescribed herein can provide a number of advantages including, but notlimited to the following. This sweat collecting device and sweatcollection and analysis system and method provide for continuousreal-time sweat sampling and analysis. The current MACRODUCT ® andMEGADUCT® products are primarily used to collect and then later measurethe concentration of sodium and chloride in the sweat of childrensuffering from cystic fibrosis. The systems and methods of the presentinvention can be used to detect a relatively unlimited number ofdifferent analytes in sweat as the sweat is generated and collected, andto monitor any changes in analytes that occur over the period ofcollection. In the methods of the present invention, sodium and chloridemay be removed as contaminants so that the instrument is better able todetect lower quantities of the analytes of interest. Other advantagesare listed throughout this description. It should be understood,however, that these advantages need not be required unless they are setforth in the appended claims.

There are numerous, non-limiting embodiments of the invention. Allembodiments, even if they are only described as being “embodiments” ofthe invention, are intended to be non-limiting (that is, there may beother embodiments in addition to these), unless they are expresslydescribed as limiting the scope of the invention. Any of the embodimentsdescribed herein can also be combined with any other embodiments in anymanner to form still other embodiments.

The term “joined”, as used herein, encompasses configurations in whichan element is directly secured to another element by affixing theelement directly to the other element; configurations in which theelement is indirectly secured to the other element by affixing theelement to intermediate member(s) which in turn are affixed to the otherelement; and configurations in which one element is integral withanother element, i.e., one element is essentially part of the otherelement. The term “joined” includes both those configurations in whichan element is temporarily joined to another element, or in which anelement is permanently joined to another element.

The disclosure of all patents, patent applications (and any patentswhich issue thereon, as well as any corresponding published foreignpatent applications), and publications mentioned throughout thisdescription are hereby incorporated by reference herein. It is expresslynot admitted, however, that any of the documents incorporated byreference herein teach or disclose the present invention.

It should be understood that every maximum numerical limitation giventhroughout this specification includes every lower numerical limitation,as if such lower numerical limitations were expressly written herein.Every minimum numerical limitation given throughout this specificationincludes every higher numerical limitation, as if such higher numericallimitations were expressly written herein. Every numerical range giventhroughout this specification includes every narrower numerical rangethat falls within such broader numerical range, as if such narrowernumerical ranges were all expressly written herein.

While the present invention has been illustrated by a description of oneor more embodiments thereof and while these embodiments have beendescribed in considerable detail, they are not intended to restrict orin any way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. The invention in its broader aspects is thereforenot limited to the specific details, representative apparatus andmethod, and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thescope of the general inventive concept.

What is claimed is:
 1. A continuous real-time sweat collection andanalysis system comprising: a sweat collecting device comprising: a mainbody having two surfaces comprising a sweat-collecting surface and anopposing outwardly-oriented surface, wherein said sweat-collectingsurface has a concave configuration which defines a rim lying whollywithin a common plane, wherein said main body has an axial boreextending between the sweat-collecting surface and theoutwardly-oriented surface; a length of sweat collector tubing havingone end joined to said main body at said axial bore and a free endextending outwardly from the outwardly-oriented surface; and aninstrument for analyzing sweat collected from a person wherein saidinstrument has an input port for receiving fluid samples, and the freeend of said sweat collector tubing is in fluid communication with theinput port of said instrument.
 2. The sweat collection and analysissystem of claim 1 wherein said instrument is a mass spectrometer.
 3. Thesweat collection and analysis system of claim 2 further comprising adevice for removing salt from the sweat that is in fluid communicationwith said sweat collecting device and said instrument and is arranged sothat sweat is transported to said device for removing salt from thesweat before it is transported to the instrument for analyzing sweat. 4.The sweat collection and analysis system of claim 3 wherein a device forremoving salt from the sweat is selected from the group consisting of:electrodialysis, micro dialysis, and ion concentration polarizationdevices.
 5. A continuous real-time method of collecting and analyzingsweat from a person's skin, said method comprising: a) attaching a sweatcollection device over an area of the person's skin, wherein said sweatcollection device comprises: a main body having two surfaces comprisinga sweat-collecting surface and an opposing outwardly-oriented surface,wherein said sweat-collecting surface has a concave configuration whichdefines a rim lying wholly within a common plane, wherein said main bodyhas an axial bore between the sweat-collecting surface and theoutwardly-oriented surface; a length of sweat collector tubing havingone end joined to said main body at said axial bore and a free end; b)placing the free end of said sweat collector tubing in fluidcommunication with the input port of an instrument for analyzing sweat;c) collecting sweat from the person's skin using said sweat collectiondevice wherein sweat travels into said sweat collector tubing and theninto said instrument; and d) analyzing the sweat collected using saidinstrument.
 6. The method of claim 5 wherein the sweat collected isanalyzed for biomarkers.
 7. The method of claim 5 wherein the sweatcollected is analyzed for ions other than sodium and chloride.
 8. Acontinuous real-time sweat collection and analysis system comprising: asweat collecting article comprising: a thin, flexible, conformable, andimpervious covering having two surfaces comprising a body-facing surfaceand an opposing outwardly-oriented surface, a central portion, edgesthat define a perimeter of said central portion, and a perimeter portionsurrounding said central portion, wherein the perimeter portion hasadhesive on the body-facing surface for adhering the covering to aperson's skin and for forming a seal around said central portion, andsaid central portion of the body-facing surface is free of adhesive; asweat collector tube having a first end, a second end, and a length thatextends between said first and second ends, wherein the first end ofsaid sweat collector tube is positioned adjacent to said covering sothat the central portion of the covering overlaps a first portion ofsaid tube and the adhesive on said perimeter portion of said coveringadheres to a second portion of said tube, and a third portion of saidtube extends outward beyond an edge of said covering to the second endof said tube, wherein the second end of said tube is free to place influid communication with an instrument for analyzing said sweat; and aninstrument for analyzing sweat collected from a person wherein saidinstrument has an input port for receiving fluid samples, and the freeend of said sweat collector tube is in fluid communication with theinput port of said instrument.
 9. The real-time sweat collection systemof claim 8 wherein said covering comprises a single piece of film. 10.The real-time sweat collection system of claim 8 wherein said coveringcomprises two pieces of flexible material comprising: a first piece offilm material forming said central portion of said covering, said firstpiece of film material having two surfaces comprising a body-facingsurface and an opposing outwardly-oriented surface, an area, and edgesthat define a perimeter of said first piece of film material; and asecond piece of film material, wherein said second piece of filmmaterial has two surfaces comprising a body-facing surface and anopposing outwardly-oriented surface, wherein said second piece of filmmaterial is sized and configured to extend beyond the edges of saidfirst piece of film material, and a first part of the body-facingsurface of the second piece of film material has an adhesive thereon foradhering to the outwardly-oriented surface of the first piece of filmmaterial, a second part of the body-facing surface of said second pieceof film material and the adhesive thereon forms the perimeter portion ofsaid covering for adhering to a person's skin and forming a seal aroundsaid central portion of said covering.
 11. The sweat collection andanalysis system of claim 8 wherein said instrument is a massspectrometer.
 12. The sweat collection and analysis system of claim 11further comprising a device for removing salt from the sweat that is influid communication with said sweat collecting device and saidinstrument and is arranged so that sweat is transported to said devicefor removing salt from the sweat before it is transported to theinstrument for analyzing sweat.
 13. The sweat collection and analysissystem of claim 12 wherein a device for removing salt from the sweat isselected from the group consisting of: electrodialysis, micro dialysis,and ion concentration polarization devices.
 14. A continuous real-timemethod of collecting and analyzing sweat from a person's skin, saidmethod comprising: a) attaching a sweat collection article over an areaof the person's skin, wherein said sweat collection article comprises: asweat collector tube having a first end and a second end, wherein thefirst end of said tube is placed adjacent the area of the person's skin,and the second end of sweat collector tube is free to place in fluidcommunication with an instrument for analyzing sweat; and a thin,flexible, conformable, and impervious covering that is positioned overand adhered to the sweat collector tube, said covering having twosurfaces comprising a body-facing surface and an opposingoutwardly-oriented surface, a central portion, edges that define aperimeter of said central portion, and a perimeter portion surroundingsaid central portion, wherein said central portion of the body-facingsurface is free of adhesive, and the central portion of the cover isplaced over the first end of the sweat collector tube, and the perimeterportion has adhesive on the body-facing surface for adhering thecovering to a person's skin and for forming a seal around said centralportion; b) placing the free second end of said sweat collector tube influid communication with the input port of an instrument for analyzingsweat; c) collecting sweat from the person's skin using said sweatcollection device wherein sweat travels into said sweat collector tubingand then into said instrument; and d) analyzing the sweat collectedusing said instrument.
 15. The method of claim 14 wherein saidinstrument is a mass spectrometer.
 16. The method of claim 15 whereinsaid mass spectrometer analyzes the sweat for analytes/ions other thansodium and chloride.
 17. A continuous real-time sweat collection andanalysis system comprising: a sweat collecting device comprising: anarticle that is to be placed in contact with an area of a person's skin,said article having a skin-facing surface, wherein said article isconfigured to collect sweat between said area of skin and saidskin-facing surface; and a sweat collector tube having one end that ispositioned adjacent to said article and in position to withdraw andtransport sweat collected between said area of skin and said skin-facingsurface of said article, said tube extending outwardly from said articleto a free end; a device for removing salt from the sweat, said devicehaving an input port and an output port, wherein the free end of thesweat collector tubing is in fluid communication with the input port ofthe device for removing salt from the sweat; and an instrument foranalyzing sweat having an input port, wherein the input port of saidinstrument is in fluid communication with the output port of the devicefor removing salt from the sweat.
 18. The continuous real-time sweatcollection and analysis system of claim 17 wherein said device isselected from the group consisting of: electrodialysis, micro dialysis,and ion concentration polarization devices.
 19. The continuous real-timesweat collection and analysis system of claim 17 wherein said instrumentis a mass spectrometer.